Project Profile: BOB.Düsseldorf Airport City – one of Germany’s most energy-efficient office buildings

Chapman Taylor created a competition-winning design for a new office development, BOB.Düsseldorf Airport City, in collaboration with Aachen-based office developers BOB efficiency design AG, which engaged Chapman Taylor to create a design for their bid. The building will be developed, built and operated according to the BOB concept, creating one of the most energy-efficient office buildings in Germany.

A BOB (Balanced Office Building) development is distinguished by a rigorous sustainability strategy. It is a serial product with individual architecture but identical technology and functionality. The indoor climate, energy concept, office modules, e-mobility concept and many other features are identical for every BOB project. In this project profile, Chapman Taylor Director Ruprecht Melder and Prokurist Andrew Mackay talk about designing the flexible, sustainable and future-proofed office building in a way which integrated the BOB template within a striking architectural design.

How did Chapman Taylor become involved with the design competition and BOB efficiency design AG?

BOB efficiency design AG is an Aachen-based company who had been impressed by our award-winning urban design proposal for Aachen city centre, Altstadtquartier Büchel, and called us for a chat about opportunities in the area. They were interested to discover that we had designed three innovative office developments at Düsseldorf Airport City – AirGate, AirView and AirPark – and they wondered if there were any more design competitions for office buildings in the area.

About six months later, BOB learned of a new design competition for an office building at the Airport City complex and we joined forces with them to create a successful design against stiff competition! This will therefore be the fourth office building that Chapman Taylor has designed for one of the most dynamic office locations in the city.

The BOB design format informed the competition design – tell us about that.

The BOB format is a mostly standard template which is used for office designs all over Germany – it places a key focus on the highest possible standards of functional, technical and environmental efficiency. What varies from project to project is the building’s form and architectural expression. We worked with the BOB template in terms of key parameters such as the fit-out grid, optimum office depth and optimum glazing specifications, while creating a striking architectural design which suits its context.

Tell us about the design concept.

The 14,750 m² GBA building offers six office floors and two underground car and bicycle parking levels. The central access core, with an open stairwell and two elevators, is bright and spacious and offers the flexibility to subdivide into as many as three units per level, with a rentable floor area starting from 230 m². The multi-space floor plan allows for a combination of cubicles, open-plan offices, team offices, quiet spaces and zones for different kinds of communication, creating a diverse range of workspaces for differing requirements.

We worked within the stipulations of the area’s zoning plan, which placed restrictions on the building height, the number of levels and other elements. The existing masterplan for the extension of Airport City envisaged a C-shaped building, which we adopted, but with interesting façade variations to give it more visual complexity.

We identified the best access points for the building, deciding against an entrance at the street because that would impede the building’s flexibility in terms of being able to subdivide easily. We formed a double-height passageway from the street into the building’s courtyard to provide access to the central access core.

The facade has been designed with a 1.35 m grid to allow efficient and flexible fit-out of the office spaces. A varied mix of wide fixed windows and narrow openable windows, offset from one level to the next, combines with solid elements in three different tones to create a vibrant appearance for the new building. We wanted a lively architecture which also conforms to the BOB concept in terms of the façade and glazing.

We have decided to use a limited colour tone palette in one material, with a little variation in the surface treatments – this gives the building a combination of vibrancy and simplicity which lends itself well to the overall BOB concept. The material will be decided according to its cost and its sustainability credentials, both in terms of the energy used to produce it and its ability to be recycled.

Very little space is wasted – for example, the BOB format uses very sophisticated, but simplified and efficient, building equipment and technology, which minimises the amount of space required for plant.

How does the building design cater for future adaptability?

BOB requires between 50% and 80% of the building to be capable of being recycled, with extensive flexibility to allow for easy reconfiguration as the market, and technology, changes.

Flexibility is at the heart of the fit-out process on BOB buildings, including the technical fit-out, with easy removal and installation possible if tenants leave or move in, or if they choose to expand or downsize their floorspace. The BOB concept provides an “off-the-shelf” manual in terms of much of the specification in the building – there are ready-made options from which tenants can pick to match their requirements.

The offices can be assembled almost like a kit set, based on the BOB concept’s module system. There are certain fixed dimensions, such as office depths and corridor widths, which allows for the building to be put together in varying configurations on each floor to suit demand. There is extensive use of demountable wall partitions to aid this flexibility (to assist with which, we avoid raised floors and suspended ceilings), allowing the building to be repurposed as the market requires and ensuring its relevance for decades to come.

The spaces can vary in size from one-person office rooms to large meeting rooms to spaces with open kitchens and social areas. The functions are essentially pre-defined by BOB and Chapman Taylor provides the framework within which they are assembled in an optimised way.

Tell us more about the environmental sustainability of the building.

The development will create one of the most energy-efficient office buildings in Germany and is expected to gain DGNB Gold certification. Electricity will be either solar or wind generated, with solar panels possibly integrated with the façade or roof.

Heating and cooling will be provided via geothermal technology – we drilled 100m below the ground, where the water temperature is about 11 ̊C and is ideal for cooling the building in the summer and heating it in the winter. The lack of a suspended ceiling and raised floor also boosts the efficiency of geothermal energy use – allowing heating or cooling to be achieved from both the ceiling and the floor, not just from one.

What makes the building a leader in terms of energy efficiency is the smart technology used. BOB has developed sophisticated software which can monitor changes in temperature and adjust accordingly as well as being able to anticipate, using algorithms, demands for heating and cooling in different parts of the building – the concrete floor activation system allows the software to predict the energy demands of specific areas.

The BOB system being uniform, it is remarkably easy for the building’s users to be able to predict their energy needs (and the associated costs) throughout the year based upon the size of the module they are using. The building is so energy efficient that users only pay 1c per square metre per month, which is a fraction of what would be expected in many other office buildings.

E-mobility is also catered for – more people will be coming to work by bicycle in years to come, and we have provided 70 bicycle stations, including 12 e-bike stations. There are also docking stations for electric cars. The design allows for easy further expansion of these facilities in the years to come, as required. This ties in with the general BOB philosophy of making provision for the invention of, or expanded use of, new technologies later in the building’s lifecycle.

What other features of the development are of note?

BOB efficiency design AG also provides a building management service. Each room in the building has a number of sensors, allowing BOB to be ahead of even the room’s users in anticipating or detecting issues which might arise. The room temperature, for example, can be adjusted ahead of time to anticipated weather changes.

Now that the competition has been won, what are the next steps?

We have just completed the preliminary design stages and are now entering the run-up to a building permit application, with a goal of beginning construction in 2021 and completing it in 2023.

More information about the BOB concept can be found at www.bob-ag.de